With the rapid development of an IP network, a capacity of an IP bearer network and the number of users keep increasing rapidly, imposing a growing demand on network bandwidth. In response to the fast growing demand on the network bandwidth, a cluster router system, a switch stacking technology, or the like is used in the prior art. For example, for the cluster router system, multiple routers are connected by using a dedicated switching matrix subrack to form a routing system; and for switch stacking, multiple switches are combined and connected by using a dedicated stacking cable to form a combined device for joint working.
However, in an actual application, the foregoing cluster router or switch stacking manner has the following technical disadvantages:
Special hardware, such as a switching matrix subrack or a stacking cable, is used for connection; therefore, a cost is relatively high and a connection structure is complex. In addition, because a system connected by using the hardware generally has a fixed system scale as required by a structure of the special hardware, adaptability to a network scale change is relatively poor, that scalability of the system is poor.